The present invention relates generally to optical scanning systems, and more particularly, to a system and method for increasing a scan rate while maintaining a minimum resolution.
Digital scanning systems, such as those used in maskless photolithographic processing, require image data to be scanned onto a subject. The scanning may occur at a defined scan rate, which may be based on factors such as mechanical limitations and the speed with which data is processed and projected onto the subject. A system may also controllably alter the scan rate to achieve different objectives.
The amount of image data that must be processed in a digital scanning system is generally relatively large, and generally increases when higher resolutions are desired. Higher resolution may be desirable for a number of reasons. For example, a line may have a minimum width when projected at a certain resolution. This minimum width may be undesirable, for instance, because it limits the number of lines which may be projected onto the subject. Using a higher resolution may allow the line to be projected using a smaller minimum width, and so more lines may be projected onto the subject. In photolithography, the subject may be a substrate and the projected image may be a mask. Therefore, a higher resolution enables a more detailed mask to be projected onto the substrate without altering the size of the substrate.
Although sometimes desirable, higher resolutions may decrease the scan rate of a scanning system because of the amount of data that must be transferred. This is especially true if the scanning system has a fixed data rate which is operable to transfer a limited amount of data.
Therefore, certain improvements are needed in digital imaging systems. For example, it is desirable to increase the scan rate of a system while maintaining a desired minimum level of resolution. It is also desirable to maintain high light intensity, to provide high productivity, and to be more flexible and reliable.